A system with many loads and many generators (say 8+ each). I need the data for generation, loads, and line flows be available. A highly meshed network is preferable.
You can follow this book. There are many standard multi bus systems data.
Title: Power System Small Signal Stability Analysis and Control
Authors: Dr. Debasish Mondal, Prof. Abhijit Chakrabarti and Dr. Aparajita Sengupta
Or can develop any mesh or network based on any standard IEEE multimachine system and run any standard load flow program like. N-R load flow program available freely online